Ship roll energy device



y 1951 J. c. PATTERSON, JR 2,554,381

SHIP ROLL ENERGY DEV'ICE Filed Jan. 14, 1948 3 Sheets-Sheet 1 mwwwg g 1951 J. c. PATTERSON, JR 2,554,381

SHIP ROLL ENERGY DEVICE Filed Jan. 14, 1948 3 Sheets-Sheet 2 J. C. PATTERSON, JR

SHIP ROLL ENERGY DEVICE May 22, 1951 3 Sheets-Sheet 3 Patented May 22, 1951 UNITED STATES PATENT OFFICE SHIP ROLL ENERGY DEVICE Joseph 0. Patterson, Jr., Alexandria, Va.

ApplicationJanuary 14, 1948, Serial No. 2,339

6 Claims. (Cl. 1140.5)

This invention relates to apparatus for storing and employing apparatus for using the rolling inertia of a ship or ships to perform work.

During the recent war a technique was developed for transferring fuel, supplies, ammunition and the like from a supply ship to a war ship while both ships continued on a parallel course at the maximum speed of the slower ship. Thi'stechnique involved the use of one or more high lines of cable fastened to the war ship and extending to a winch on the supply ship. Goods were passed from the supply ship to the war ship while supported on the high cable. The winch on the supply ship was manually controlled and an effort was made to maintain SllfilClEIlb tension in the high line to prevent the cable-borne load carrier from hitting the water and to prevent excessive cable-stresses. Naturally, to keep the line well above the water, it was led OE and on the ships at points high in their superstructure or from cargo booms. Thus, with two ships tied together high up on the structure, considerable motion is encountered, especially when the roll of the two ships is opposite. To maintain a predetermined cable tension to support the load to prevent overstressing of the cable and to pay out and retrieve cable as required by the relative movements of the ships, automatic tension Winches must be used, these winches being subject to overhaul when the cable tension'exceeds a predetermined value and serving to take up automatically when the cable tension falls below a predetermined value.

Automatic tension winche of small capacity are now known, but the use of the high line system of supplying one ship from another while both proceed has been hampered because of the very high horsepower requirements of the winches when used with high lines between rolling ships. For instance, if a tension of 12,000 pounds and a speed of 600 feet per minute is to be maintained, 250 to 300 horsepower is required at the winch; depending on the over-all efficiency, and this is usually too high a requirement for the generators of a supply ship since four to six winches per ship are required. To install extra generators just to operate the winches is, of course, possible but is not economically feasible.

It is proposed therefore, as a part of the present invention, to store the energy of the power generated incident to that portion of the cycle of roll of the ships when they are moving apart and the cable is being pulled out, and to convert thi energy back to power to reel in the cable and to overcome all ofthe friction losses of the 2 system so that the generators of the ships will not be required to furnish any of the power required in maintaining the transfer cable in position.

A more general object of this invention is to store the energy of ship roll and to convert the stored energy to power to meet, or to assist in meeting, any power requirement later encountered.

It is contemplated, according to the present invention, to cause the cable of a high line or the like to do work on a winch or the like during a portion of the roll cycle of a ship and to convert a portion of the work to potential energy which is stored for later use.

It is a further object of thepresent invention to provide means supplied with energy from ship roll to control the tension on a high line cable.

It is likewise an object of this invention to provide a work-energy converter which can be adjusted to store energy and perform work at a rate depending upon the operational requirements at any given time so that when used with a high line cable the tension on the cable can be maintained at a lower value under light load conditions than under heavy load conditions.

Other objects and advantages-of this invention will be apparent upon consideration of the followingdetailed description of several embodiments thereof in conjunction with the annexed drawings wherein:

Figure 1 is a schematic end view of a high line transfer cable extending between two ships, the broken line indications serving to illustrate several different positions of the cable support at various stages in the roll cycle;

Figure 2 is a schematic view partially in section of simplified apparatus according to the present invention for demonstrating the principles of operation in receiving energy from and supplying energy to a cable winch used to control line tension in a transfer cable of the type shown in Figure 1;'

Figure 3 is a view similar to Figure 1 but illustrating an embodiment of the invention adapted for practical use to control either or both of two cable winches of the type previously mentioned;

Figure 4 is a detail'sectional view of the control valve system for the assembly of Figure 3 shown in its locking position;

Figure 5 is a detailed sectional View of the control valve system for the assembly of Figure 3 shown in its reversed position as used during rigglng;

Figure 6 is a schematic-view similar to Figure 3 but illustrating a modified type of stroke control in conjunction with the parallel piston type hydraulic motor; and

Figure '7 is a view similar to Figure 6 but showing a difierent position of the stroke control mechanism.

Referring now in detail to Figures 1 and 2, a pair of ships l and H are shown, these ships, in the operation of the device, being in motion and proceeding on course although connected by a cable I2 extending from a winch 13 on the ship l0 over a guiding pulley l4 on that ship to and over a guiding pulley l5 on the ship I I, and from thence to an anchor point. Operating on the cable there is shown a cable car l6 which is merely a diagrammatic indication of any sort of cable-supported conveying device for moving supplies or the like from one ship to the other.

If now reference is made to the pulleys l4 and I5, it will be noted that when the ships are erect, they will be in the full line positions. If now the ships are rolling oppositely, the pulley [5 will move to the position a while the pulley I4 is moving to the position I4a. This will require that considerable length of cable [2 be payed out from the winch [3. In the opposite cycle of the roll, that is, when the ships are rolling toward one another, the pulley l4will move from the position shown in full lines to the position I 41) while at the same time the pulley [5 will move to the position l5b. It is perfectly apparent that as the pulleys move apart, as indicated in Figure 1, work is done on the cable which causes the winch to rotate. On the other hand, as the ships move toward one another, if the cable is to be maintained taut, the winch must do work on the cable to take up the slack.

Naturally, the horsepower requirements of the winch mechanism will vary considerably with the tension on the cable, the load which it is supporting, and the magnitude and rate of the ship roll. In Figure 1 the roll axis of the ship I0 is indicated at Illa and the roll axis of the ship I l is indicated at l l a.

If now reference is made to Figure 2, it will be noted that the winch I3 includes a drum I1 mounted on an axle [8 which is journaled for rotation in bearings diagrammatically indicated. One end of the axle I8 is attached to a gear l9 which meshes with a gear mounted on the drive shaft 2| of a unit 22 of a parallel piston type pump-motor unit. The unit 22 comprises a non-rotating wobble plate 23 and the piston and cylinder assembly rotatable with the shaft 21-.

The piston and cylinder assembly includes pistons 24 and 25 operating in cylinders 26 and 21 respectively. Ahydraulic conduit 2B leads from the unit 22 to the receiving end 29 of a hydraulic accumulator 30. The accumulator contains a piston 3| having a portion 32 of small diameter operating in the working space of the end 29 and a portion 33 of enlarged diameter working in an enlargedupper portion 34 thereof. The top of the upper portion 34 of the accumulator is connected through a conduit 35 to a compressed air or gas container 36. Between the unit 22 and the pressure accumulator 30 the line 28 is provided with a T-connection 31 which leads to a normally spring closed check valve 38. Beyond the check valve a conduit 39 leads into a storage reservoir 40 for the working liquid of the system. Another conduit leads from the bottom of the storage reservoir back to the unit 22. The conduits 28 and 4| are connected to arcuate valve grooves 42 and 43 respectively. These grooves,

coacting with ports at the bottom of the cylinders 25 and 26, control the flow of liquid through the unit. The details of the valve grooves 42 and 43 have not been illustrated since they constitute a conventional and well-known arrangement which, per se, forms no part of the present invention. For a description of the details of a hydraulic unit of the type shown schematically in Figure '2, reference is made to Janney Patent No. 1,020,285 and particularly to Figure 4 thereof.

In operation it is apparent that when the cable 12 is pulled out, as indicated by the arrow in Figure 2, the drum will be caused to rotate and this rotation, through gears I9 and 20, will be imparted to the piston and cylinder assembly of the unit 22. As the assembly rotates from the position shown in Figure 2, the piston 25 will gradually move to the left, while the piston 24 will move to the right. Thus, the piston 25 will effect a suction stroke, while the piston 24 will effect a discharge stroke. The suction stroke will draw fluid from the reservoir 46 of the piston and cylinder assembly while the discharge stroke of the piston 24 will pump liquid through the conduit 28 into the accumulator. It is apparent that the cyclic operation of the pistons in the cylinders is such that each piston and cylinder goes through itscomplete cycle in 360 of rotation. The output of the unit, therefore, is the output of the full displacement of both pistons for each rotation of the shaft 2|. The valves 42 and 43 control the proper distribution of the liquids. In.

other words, as piston 24 moves inwardly from the position shown in Figure 2, it stays in communication with channel 42 until it has almost completed its stroke to the right. Shortly after this it is placed in communication with the chan nel 43 and starts the intake stroke.

As pressure liquid builds up in the lower portion 29 of the accumulator 30, the piston 3| of the accumulator is gradually moved upward bringing about compression of the gas occupying the working space in the upper portion 34 of the accumulator. In order to keep the accumulator Within reasonable size limits, the storage tank 36 is connected to the gas chamber of the accumulator, and the gas is therefore compressed in the upper portion of the accumulator, in the conduit 35 and in the storage tank 36. The storage of energy in the accumulator 30 continues so long as the cable 12 is being pulled out and work is being done on the drum ll by virtue of the roll of the ships. When, however, the ships roll toward one another, and it is necessary for the cable to be reeled in, the piston 3| of the accumulator is forced down under the pressure of gas in its upper chamber and liquid is pumped through the conduit 28 into the unit 22 through the pistons and cylinders, and out into the storage reservoir 40. This action imparts rotation to the shaft 21 by causing rotation of the piston and cylinder assembly, and the rotation through the gears 26 and I9 is applied to the shaft l8 of the drum l7, causing cable to be reeled in. In other Words, when cable is being pulled out the unit 22 functions as a pump to charge the accumulator, and when cable is being reeled in the unit 22 functions as a motor to drive the drum H. The valve 38 is simply a pressure relief which operates only when pressure in the line 28 becomes dangerously high.

With the invention exactly as it is shown in Figure 2, it is quite apparent that the pressure loss in the accumulator caused by a single cycle of reelingiin; will not-bemade; up-

alsingle cycle;- of pullingout due; to thezufact that there is some frictionzloss in the system andthe work done by the :cable: isjust about equal to-the work .done on the cable... It is forv thatreasonthat the liquid during .the pulling: out. operationfthaniis required. to be done during'the .reelingxinoperation; f'riction losses. could be made upandin factya considerable. excess :of. energy could-:be made available. Thus, it-is highly desirable that the piston and cylinder unit associated "with? the .cable' drum be provided with strokecontroliapparatus. Likewise, it. is desirable to render. the operation of the hydraulicpiston and: cylinder unit adjustable so that not only. will; it. operate during the actual periods whenwthe .line'is maintained, but also, in conjunction with another unit, during those periods when the line isbeing rigged in the firstiinstance, and when it is being hauled: aboard after the transfer: of. supplies has been effected. Accordingly, in Figure 3 there is shown a modification of' the present invention of the type susceptible of practical useon board ships.

In Figure 3 there are shown two drums 50- and 51 connectedby gear trains 52. and 53. to parallel piston hydraulic units 54 and..55 respectively.- The drums 50' and 5!: and the associated gear trains 52 and 53' correspond in structure and function to the drum I1 and the gear train comprised of gears 19 and 20. The units 54 and 55 correspond generally in structure and in function to the unit 22, except that stroke control apparatus isassociated with the-wobble plate of each of units 54 and 55. The stroke control apparatus isgenerallydesignated atv 56 and- 51. units are connected to piston valves 58- and .59 respectively and from these valves there" extend conduits 60, El, 62 and 63. The conduits 6B and 62 lead to a selector valve 64, while the conduits Bl. andv 63 lead to a selector. valvev65. r

The selectorvalves .64 and 65. are connected'to conduits 66 and 6'! and .are so designed-that either or both of conduits 60 and 62. canabe placed in communication with conduit 66.. and

either or both of conduits 6| and. 637 in com.-

munication with conduit. 61. Thus. it. is that the drums 50and 5-I'may be operated separately or together, depending; upon. the operationalrequirements at any given time.

The. conduit 66 leads .to a'pressure accumulator 68 corresponding. instructure: and .-function to the accumulator 311 shown in. Figure 2. A parallel piston hydraulic unit 69. is;pr.ovided.ito effect the initial charging of thesystem and to provide .a. pump. to furnishroil. energy. to v operate the main. hydraulicxunitixso that the winches .can be. operated. by suitable adjustment of the valves 58 and '59 without lchargingxthe accumulator. The. unit. 69 is driven. from: an electric motor. 10. through. a. shaft; H.

Now .referringin detail .to. the control :piston valve assembly 58, it will be noted that this assembly is-connected to lines TI; and. 12 extendeingfrom the unit 54., and. is.likewise connected to lines 60 and BI previously discussed.=:.: The

The output lines:from the hydraulic valveis comprised --of ahollow bodya13- andga plunger M manually-operated: by acontrol lever 15 pivoted at 16 to one end of. the-plunger. 1:4 and fulcrumed at 1.5a. Thus,.by rocking the lever 15 about its axis: at 15a; .itis. possible to adjust the valve vto the three positionsgshown in Figures 3, 4 and 5. In the Figure 3 position the pistons H, 18 and 19 of the plunger 14 coact with annular grooves in the valve body 13 so that flow is established from line H through the valve body to line 60, and from line 6| through the valve'body to line. 12. This, it will be recognized, is the normal automaticoperation position which will cause the unit-54 to operate in the manner described in. connectio with the-unit 22 of Figure-2.

If the valve operating lever 15. is-movedclockwise from the Eigure 3 position to. the Figure 4 position, pistons 18 and 19 of the valve plunger M block conduits 60 and 6% respectively. Through channels 88, '8'! and 82 the line 68 is'connected with both ends of the plunger M- so that nopressure difference can exist tending to. move the valve from its position of adjustment. In the Figure 4 position both of conduits 'H- and 12 are cut on at the valve.

If new the operating lever. 15 is moved still further clockwise to theFigureb position, then conduit H is in communication 'withconduit 6|, and conduit 12, through. channel 82, is in communication with conduitfifl. Thus. it isthat in the Figure 5'position0f the control valve the relationship of the conduits-1 I: and 12 to the conduits ti) and 5| is reversed from-the'relationship existing in the Figured position ofithe valve.

The foregoing description. has zbeen devoted entirely to control valve 58-, but it is to be understood that control valve 59 is constructed and operates in the same manner.

The stroke controlling 'mechanism; 56 which is associated with .theunit 54, comprises. a rod. 33 connected tothe'wobble plate 84' and having at its other end --a piston-85' operating within a cylinder 8'5. The'cylinder 86 contains a coil spring 87 which normally urges the piston 85. in the direct-ion of the arrow in FigureB. On the opposite side of the piston 85 from the spring 81 there is a working space which is connected by a line 88. to the line H. It is. now' apparent that so long as the pressure'existing in the line 88 is insufiicient to overcome the thrust of the spring 8?. piston '85 will be urged: downwardly and the stroke of the pistons and cylindersofrthe unit 54 will be at maximum. "When, however, the pressure in the line H' builds; up. the piston 85 is moved upwardly against the thrust of spring 8'5 and the strokeis gradually decreased. The stroke control system describedi'in connection with control mechanism 56 is also employed in connection with control mechanism 51 and to another controlinechanism 89 applied to the wobble plate of the transmissions). In eachof these cases a vent is provided for the chamber-containing the spring.

The pressure exerted on the piston of the stroke controlimechanism '89 is derived from. the line 66. througha connecting conduit $39. Another conduit 9.1 branches "from the conduit 65" and leads to a. check valve.- 92 and. from the check valve 92 througha conduit '93. to. one side of the hydraulicpump 69. The other side ofthe pump is connected to conduit 61 andthrough a branch 94 from that conduit to a working liquidareservoir 95. A returnline 96- extends from the reservoir. 95' to a reliefvalve 95- and from-there back 7 into the line 9|. A shut off valve 91 is located in the line 66 between the branch 99 and the accumulator 68.

When now the apparatus of Figures 3, 4 and 5 is to be put into use, it is first necessary to pump pressure liquid from low pressure tank 95 to the accumulator 68. To do this, the required amount of air or gas is introduced on top of the accumulator, valve 91 is opened and piston control valve 58 is set to the Figure 4 position in which lines 1| and 12 from the unit 54 are blocked. The motor is started and unit 69 pumps liquid from reservoir 95 through lines 93, 9| and 66 into the bottom chamber of the accumulator. Naturally to insure this operation of the unit 69 it is also necessary either to set the valves 64 and 65 so that conduits 52 and 63 are cut off, or to adjust the piston valve 59 to the Figure 4 position.

The action of the unit 69 continues until the accumulator is fully charged. During the charging operation, the pressure in the line 99 gradually rises causing the stroke control mechanism 89 to adjust the wobble plate of the unit 59 toward zero stroke which is finally achieved when the accumulator is fully charged.

When the pressure in the accumulator 69 has reached the desired value, the next step in the operation is to pay out cable so that a line can be established from one ship to the other. To do this, assuming that only drum 59 is to be operated upon, it is necessary to close valve 91, to adjust valves 64 and 65 to block lines 52 and 53 so that flow is established from line 59' to line 65 and from line 6| to line 61, and to set control valve 58 to the Figure 5 position. With this preadjustment, the motor 1|] causes the hydraulic unit 69, operating as a pump, to pump liquid drawn from the reservoir 95 through conduits 94, 93, 9|, 56, 60 and 12 to the unit 54 to cause that unit to drive the drum 50 in the paying out direction. The exhaust from the unit 59 goes through lines 1|, 6| and 61 back to the unit 69 or reservoir. This operation is continued until the line is payed out sufficiently to establish a connection to the other ship. While the connection is being established, the control valve 58 is adjusted to the Figure '4 position so that the drum 50 is immobilized. Of course sufficient slack cable will be available to eifect the connection. Immediately after the connection is effected, the valve 58 is shifted to the Figure 3 position and valve 91 is opened. During the transfer operation the drum 5|] will now operate in the manner described in connection with the drum H of Figure 2, that is, liquid will be drawn through conduits 94, 61, 6| and 12 into the unit 54 and pumped out through conduits 1|, 60 and 66 to the accumulator during that portion of the roll cycle when cable is being pulled out. During the portion of the roll cycle when cable is reeled in, the unit 54 is supplied with pressure fluid from accumulator 68 through conduits 66, 60 and 1| and this liquid is returned to the reservoir 95 through conduits 12, BI, 61 and 94.

Throughout the loading period, while the cable I2 is extending from one ship to the other, the piston control valve 58 is left in the Figure 3 position and motor 10 is kept running. Although the motor 10 is kept running, the rolling inertia of the ship provides ample power through the accumulator 68 to operate the drum 59 when reeling in is required, the motor 19 serving only to provide a safety factor. The power supply to the motor 10 during theautomatic operation is extremely low due to the fact that the pressure in the line 66 acting on the stroke control device 89, keeps the unit 69 at zero stroke so that the load on the motor 1|] is only that imposed by its own friction and that of the unit 59. Should conditions occur where the roll does not keep the pressure in the system to the desired value, motor 10 acts as a helper to keep the accumulator charged. These conditions result from the nature of the cable used. In other words, although the roll of the ships can afford ample power to compensate for the work which must be done when cable is reeled in, there may be practical limitations on the sizeof the cable which mean that excessive cable tensions cannot be tolerated, which in turn reduces the efiective output horsepower of the hydraulic units during the accumulator changing portion of their operating cycle. If heavy enough cable is used, it is quite possible to shut down the motor 19 during the loading period so that all of the cable tensioning is accomplished by pressure liquid stored in the accumulator during the portions of the roll cycle when cable is being pulled out.

It will be noted that the stroke control device 56 associated with the unit 54 increases the stroke as pressure decreases in the line 1|. Thus, during reeling in of the cable when the pressure in the line 1| drops, the stroke of unit 54 is increased so that the unit 54 pumps the maximum amount of working liquid. In other words, during reeling in, the pressure in the accumulator falls and the stroking device 56 sets the unit 54' on a high stroke angle. This stroke angle exists, therefore, at the beginning of the pulling out operation so that a maximum amount of oil is pumped back to the accumulator. It is also desirable to maintain a high stroke when pressure is 'low in order to obtain maximum torque output at low pressure, for in a hydraulic motor the torque output falls ofi for a given pressure as the stroke is reduced. The stroke compensator 56, therefore, acts as a torque-adjusting means to afford a constant torque output as the pressure varies.

It can now be seen that the stroke control apparatus associated with the units 54 and 55 is automatically adjusted, in accordance with the teachings of the present invention, so that during the pulling out cycle when energy is being supplied to the accumulator, the stroke is high and the energy stored is great, while during reeling in when energy is expended from the accumulator, the stroke is such that less energy is spent than that which is stored. The apparatus can therefore be adjusted exactly to compensate for the friction losses of the system so that under ordinary conditions of operation no output from the unit 69 will be required during the entire transfer operation.

In the foregoing discussion nothing has been said regarding the operation of the drum 5|. If the drum 5| is to be operated in lieuof the drum 50, the procedure will be as outlined above except that the valves 64 and 65 will be adjusted to connect control valve 59 rather than control valve 58to the accumulator system. If both of drums 5|] and 5| are to be used concurrently, the valves 64 and 55 are adjusted to connect both of valves 58 and 59 to the accumulator system in parallel. It is likewise apparent that any number of cable drums may be operated in like manner bya suitable parallel connection to the accumulator system, it being understood that the more drums to be served, the larger the accumulator system will have to be.

After the transfer "of -'loads =from one ship to the other has been completed and it isdesired to reel in the cable, thecable is disconnected from the receiving *ship and is reeled in by the action of the accumulator until' the supply of pressure fluid therein is exhausted, at which time, if necessary, themotor 10 and theunit "69 take over to complete the "reeling 'in' operation.

In the foregoing-discussion no mention has been made "of the function of valves 92 and 96; Actually, the valve 92 isused to prevent high pressure working liquid from the accumulator from reaching'the unit'6'9',*whi-le a relief valve such as '96 is provided for safetys -sake in case the pressure in the system becomes excessive.

Now referring to Figures 6and '7,- there is shown a hydraulic system similar to that described in conjunction with Figure L3, but involving a different type of control apparatus for the main unit which is attached to the winch. In Figure 6 the hydraulic unit,- which corresponds in structure and'function-to the unit 54 of -F'igure '3, is designated by the numeral I00. The unit is connected through conduits I 'OI 'and I02 --to a piston valve I03 corresponding in structure-and-function to the piston valve 58. The piston valve is also connected to conduits I 04 and I05, corresponding in structure and function to 61 "and 60 respectively. A stroke-control-device IIlSis provided, said'devi'ce having apiston 101' and a piston rod I 08 attached-pivotally at I09'to the wobble plate of the unit I; -The piston I01 is normally urged upwardly by-acoil spring- I I0 sothat the normal bias is to maintain the wobble platein-the zero stroke position; The cylinder III in which-the piston I01 operates, afiords'aworking space H2 above the piston I01 and this working space is connected through a conduit I I 3 to a piston valve I I4. The piston valve-is connected to the conduit IOI by conduits H5 and H6 and a check valve I I1 is placed in the conduit I0 I between the point of attachment of conduit I I5 and the'point of attachment of conduit H6. I Anotherconduit II8 extends from the piston valve II'4-to the conduit I04.

By the arrangement 'just described the hydraulic unit I00 can be put on high stroke during pulling out so that it will pump a larger quantity of oil during that period than the oil'which is used during retrieving. The control valve H4 and the check .valve II"! together provide means of registering the'direction-of oilflow. This allows the .control'device I06 to introduce pressure on top *oftheistroke controlpiston- I01 during pulling out.

More specifically, during pulling out, when the drum :is'driving the unit [.00 and thetunit I00 is functioning as a pump, liquid .is being forced in the direction of the arrow of Figure 6 in line IOI. Since valve I'I'Lis closed, the liquid flows into line NH and up line II5 to act on a plunger II9 located in uvalve'I I4. --The plunger I I9is. normally .biased by a spring- I20 into the position shown in Figure 7, but whenzpressure is supplied through the conduit ,I I5, spring I20 is compressed and the plunger II-9' assumes the Figure 6 position. In this position the plunger H9 establishes flow from conduit II5 .ithrough conduit I'I3 tov working .space H2, whereby as pulling out occurs pressure is introduced in working space H2 and the unit-I00 is urged to the maximum stroke position. On the other hand, during reelingin -or retrieving the liquid in conduit IIJI isflowing toward the unit I00 instead of away from it. Thus;-valve II--'! is opened and liquid flows through conduitIIl'I and exerts pressure in parallel through conduits H5 and H6. This being the case, valve plunger H9 under the bias of spring I20 remains in the Figure 7 position cutting off pressure in conduit '3 so that spring H0 returns the piston III! to the upper position and 'restores -the wobble plate of the unit I00 to a lower-stroke position.

'In Figures Band 'Y-there-isshownin association with'the tilt plateinechanism apairof adjustable stops I2I and I22. These stops act on'a tongue I23 extending from the wobble plateof the'unit I80. These stops function to adjust thes'troke so that the correct stroke for oil pumping'and torque output for any given pressure can be achieved by adjustment. The advantageof the stops 'I2I Land I22 will be appreciated when it is borne in mind that the-load imposed on the cable connecting the two ships will vary with thena'ture of the cargo being transferred. If the load conditions are light, the cable can-be maintained in the predetermined position by subjecting it to much less tension than is required when the load is great. If a light loadJis encountered, the stops I2! and I22 are so adjusted that thestroke of the unit Ill?! is-"kept short, thereby reducing the load imposed on the cable and allowing the: entire system tooperate atlessthan capacity. The stopsIZl and" I22 do not prevent the unit I00 fromoperating at full capacity, since if a .full capacity iloadsis encountered, it; is necessaryonly to. adjust the stops to permit maximumstroke operation. It is to beunderstood of course. that the .stops need-1 not beassociated with the. tongue I2.3.but .can:be associated with any part of a wobble plate assembly.

In the foregoing discussion of the operation of the piston valve I I I,:the details of construction of that valve were .notdescribed .and, in fact, they aresusceptible ofssome modification. However, the form shown in Figure .6 includes in the valve body a channel I23, and in the piston, radialv ports l24-communicating .withthe central core in which the. sprin I20 .is mounted. It can be seen therefore that when pressure liquid is flowing, as indicated in'Figur -fi, pressure is exertedon the bottom. of the piston 'I I9; and through theport I23, and an annular groove in the piston: H9, this liquid is made available to the line II 3 and the workingspace I'I2. --Most of I the pressure liquid, however, :fiows out through line Ilfi back into line I 5I on the other side of the valve III. In the Figure 6 position line II8, through radial channel I25, is in communication Wlth the center of the pistonIIS wherein liquid from line H8 is trapped.

In the Figure 7 position communication is established from 'line II3 to line H8,- and in this way liquid dispelled from working space H2 is returned to the system at line "34. The liquid inline ltl continues through lin 5 to act on the bottom of the piston, but because of ports In and line H6, this same liquid also operates on the other side of-the piston.

'It will be "understood that the foregoing description is demonstrative of the invention but isnot'nearly indicative of all of the forms'which it may'assume. Thus, not only are the principles "of the present-invention utilizable in-connection with the pulling out and reeling in of cable, but they are of wide general'utility' inemploying the rolling inertia of ships to' provide means to meet someor all of the power requirements of it. Throughout the specification reference has been made to hydraulic units of the parallel piston type. It is quite apparent, however, that other types of hydraulic units such as the radial type can be used or that the entire system be operated by electrical rather than by mechanical means.

What is claimed is:

1. In combination, a ship, a piston and cylinder type hydraulic work-energy converter of the type equipped with means to vary the stroke of the pistons to vary the energy output of the converter, said converter including a winch mounted on a portion of the ship, a structure separate from the ship and including a connection point relatively movable in response to waveinduced roll with respect to said winch, a cable connecting said winch and extending between said converter and said connection point so that the, converter is driven when said portion and said point move relatively away from one another and the converter causes the winch to reel in cable when said portion and said point move relatively toward one another, a hydraulic accumulator, means connecting said accumulator to said converter, and means responsive to a pressure change in said connecting means to control the stroke of the pistons of the converter.

2. In combination, a ship, a hydraulic Workenergy converter of the piston and cylinder type equipped with means to vary the stroke of the pistons to vary the energy output of the converter, said converter including a Winch mounted on a portion of the ship spaced from the axis of roll, a structure separate from the ship and including a connection point relatively movable in response to wave-induced roll with respect to said portion of the ship, a capable connecting said winch and extending between said converter and said connection point so that the converter is driven when said portion and said point move relatively away from one another and the converter causes the winch to reel in cable when said portion and said point move relatively toward one another, a hydraulic accumulator, conduits connecting said accumulator to said converter and means responsive to the direction of flow in one of said connecting conduits to control the stroke of the pistons of said converter.

3. In combination, a ship, a hydraulicworkenergy converter of the piston and cylinder type equipped with means to vary the stroke of the pistons to vary the energy output of the converter, said converter including a winch mounted on a portion of the ship spaced from the axis of roll, a structure separate from the ship and including a connection point relatively movable in response to wave-induced roll with respect to said portion of the ship, a cable connecting said winch and extending between said converter and said connection point so that the converter is driven when said portion and said point move relatively away from one another and the converter causes the winch to reel in cable when said portion and said point move relatively toward one another, a hydraulic accumulator, a reservoir, a conduit connecting said accumulator to said converter, another conduit connecting said converter to said reservoir, means responsive to decrease in pressure in the conduit connecting said accumulator and converter for increasing the piston stroke of said converter.

4. In combination, a ship, a hydraulic workenergy converter means to vary the conversion ratio of said converter, adjustablemeans to limit another and the converter causes the winch to reel in cable when the winch and the point move relatively toward one another, a hydraulic accumulator, conduits connecting said accumulator to said converter, pressure responsive means normally biasing said conversion varying means to-- ward the minimum conversion ratio, valve means responsive to one direction of flow in one of said conduits for applying pressure from said conduits to said pressure responsive means to overcome said biasing means and cause the conversion factor to increase and responsive to the other direction of flow in said one of said conduits to isolate said pressure responsive means from the pressure in said one of said conduits so that the biasing means is efiective.

5. In combination, a ship susceptible to generally cyclic motion, a mass remote from the ship, said mass constrained to motion differing from that of the ship, means interconnecting the mass and the ship, a work to energy converter connected to the connecting means, energy storing means connected to said converter to receive energy therefrom, a load connected to said energy storing means, said mass constituting means responsive to one portion of the cyclic motion of the ship connected to drive said converter to cause it to supply energy to said storage means, load-responsive means for controlling the energy output of the converter and means for adjusting the range of operation of the loadresponsive controlling means.

6. In the combination of a floating element subject to wave action, a work to energy converter on said element, said converter being adjustable as to energy input and work output, energy storing means to receive energy from said converter and means responsive to wave induced movement of the floating element to do work on said converter to cause it to deliver energy to said storing means, said converter including means movable in response to changes in the magnitude of the energy stored in said storing means and linkage means connected to said movablemeans and to said converter and controlled by said movable means to adjust the rate of energy output of said converter to said energy storing means in inverse proportion to the magnitude of the energy stored in said storing means.

JOSEPH C. PATTERSON, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Date Number Name Re. 20,551 Rouse Nov. 9, 1937 412,113 Murphy Oct. 1, 1889 619,073 Deering Feb. 7, 1899 619,074 Deering Feb. 7, 1899 623,267 Walsh Apr. 18, 1899 662,774 Davis Nov. 27, 1900 2,272,785 Zoll Feb. 10, 1942 2,479,316 Connolly Aug. 16, 1949 

